Two years ago I acquired this lot of systems from someone who stored them in his flat and apparently didn't use them for 20 years:

Among these were 3 computers assembled by a French company called "ADDX Systèmes". From what I've read they were around since the early '80s and were making Z80-based systems back then.The three systems were fairly yellowed and smelly, having been stored in a kitchen for some of them. Two were 286-20 models with identical specifications (dated late 89 - early 90) and one was a later 286-12 model (dated 1991). Last Christmas I finally had some time to look into them and decided to begin with one of the 286-20:

To my surprise it booted straight away - the rechargeable battery even remembering the CMOS settings for a few hours (not bad for a 1989 motherboard!).There also seemed to be little to no leakage from the battery so the motherboard was in great condition.Here's a picture before removing the barrel battery and cleaning the whole thing (I'd be grateful if one of you could identify the board BTW!)

The video card is an 8-bit Orchid Designer 800 (Tseng ET3000AX based) with dual DB15/DB9 connectors.I haven't been able to trace the manual online so I don't know how to configure the DIP switches for EGA output (it is set to VGA at the moment).

We also have a parallel / serial interface card:

And a Western Digital Floppy / Winchester interface, driving a single 3.5" 1.44Mb FDD and a Kalok KL-320 MFM 20Mb Hard Disk.The original Toshiba FDD didn't seem to work so I replaced it with a later model.The Kalok HDD on the other hand works beautifully (no bad sectors according to Scandisk) and makes a very pleasing sound

PSU is a "Soletek LYP-200B" - I cleaned the inside with compressed air.

What's cool is that the different parts are all dated with a sticker on each of them. This shows the system has been pretty much left in the state it left the factory in, and was never upgraded.

Once the photos were done I disassembled the whole thing, cleaned the mainboard and the expansion cards in soapy water, cleaned the case with CIF cream and then attempted the retrobright treatment on the case bezel. This got some of the yellowing out, but not all of it. However I'm glad I stopped at this stage as I found it's very easy to overdo it (as we'll see later).

After everything was clean and dry, it was time to reassemble the system and make a few upgrades, while keeping the period-correct look of the machine:

- Replacing the barrel battery with an external battery- Adding a 5.25" FDD- Replacing the Orchid 8-bit VGA with a Tseng ET4000 I found in another machine from the same seller- Adding a Sound Blaster 2.0 CT1350B- Adding a 3Com 3C509 Network adapter for easy file transfer using M. Brutman mTCP

Overall it's a nice little system - the case feels quite solid and makes all the right sounds (loud PSU and HDD). I suppose it wasn't so cheap back then. The 20Mb HDD is quite limiting but I only have a few games on it at the moment. It's been fun discovering a class of machine I've never had experience with - as a kid my parents went from XT to 386SX16 and we skipped the 286-era altogether.

Thanks! Quality wise these mainboards definitely feel a notch above others I have from this era. Case in point, all 3 mainboards from these ADDX systems are still functional, whereas it's only a 50% working rate for the other machines I've been working on (I also bought another lot of 10 systems from the same seller on a later occasion).

I even got another spare board from this person, so I actually have 4 working boards like this one (two 286-20 and two 286-12). On the other 286-20 board I've installed some SIPP modules and they seem to play along nicely with the DIP modules, as it gives a RAM count of 2Mb - I am not sure about the maximum these boards will allow.

I don't know about WS0 or EMS emulation - there is an extended CMOS setup option (NEAT Chipset setup program) but I don't really understand the options and I haven't investigated yet. There are various settings for Processor Clock, Bus Clock and DMA clock among others. I'll take a screenshot of the menu next time I have access to the machine, and would definitely appreciate any help in optimizing the system

My plan was to originally use it this PC as an EGA rig, but I found out that a 286-12 is actually better suited to this task. There are a few games I want to play that are speed sensitive and seem to work a bit too fast with a 20mhz clock speed (Deathtrack for example). I will post another thread about the 286-12 soon.

In the mean time here are two more screens I omitted from the original post - it shows the system is currently configured for 1 wait state if I understand correctly.

Nice Sony display. I had one that was basically identical on my first PC, but without the Sony badge.

Thanks. Our first VGA monitor was also the same model as this (Sony CPD-1420E). I got this one from the local classifieds a few years ago, but unfortunately it's past its prime and severely lacking contrast - the blacks are not black anymore but grey. I am not sure I'll keep it as it's quite disappointing to use in this state.

Note that CMOS setup says the RAM is located in Bank 0 and 1 so I'm wondering if there's a jumper on the board that inverts location of the primary and secondary banks?

Dr. Hard: 3069 Hardstones

I've never been familiar with the concepts of Shadowing and Interleave but I thought it would be a good opportunity to learn

First thing I noticed is that when I enabled Interleave the performance actually dropped (around 2500 Hardstones). I also enabled BIOS and Video Shadowing and got beeps at POST with "CMOS Memory Size Mismatch" error and HIMEM.SYS refusing to load on startup.

I understood I might need more than 1MB RAM to successfully enable shadowing, and that maybe Interleave would work only with the 4 RAM Banks populated.

So I harvested some SIPP sticks from another board:

Found a board on stason.org that, although not identical, has a similar layout.

I switched the JP9 jumpers to the "B" setting and added the SIPP sticks, then proceeded to change the settings one by one - 2-way Interleave, 0 wait states, 4-way Interleave, BIOS F0000H 64k Shadowing, Video C0000H 16k and Video C4000H 16k Shadowing. Each change actually made a difference with 0 wait states and Memory Interleave being the most noticeable. The system feels so much snappier now - DOS and programs load much more quickly.

I wonder if putting faster RAM (80ns or lower) would still increase the performance? Also, there are many more settings in the XCMOS Neat Setup so there might be a way to make things even faster. They look quite complex though and I'm not sure what they do. There are many EMS related settings but I haven't experimented with any of them yet.

Anonymous Coward wrote:Putting in faster RAM will only help if there is a way to reduce the number of wait states.

Good to know. I guess since the system appears to be stable at 0 wait states it wouldn't make any difference.

On another note I have been messing around with the EMS settings and installed the supposedly correct EMS driver for the C&T Neat 286 chipset (called EMM.SYS) but regardless of the configuration it won't give any EMS. I guess I need to try another driver...

Very nice system! The trinitron monitor is beautiful and i bet the picture looks amazing in person.

As far as the performance of the system i'm not too impressed. My 16 MHz AT clone based on a Octek Fox II board with Headland HT12 chipset scores 4044 Dhrystones in NSSI. Simply overclocked to 18MHz i get a score of 4512 Dhrystones. I've had an even slower 20 MHz board much slower than yours, the infamous M219 board. The chipset seems to be very important, as far as i know, Headland and VLSI seem to be the fastest. My graphics subsystem is probably much slower than yours though, since i use a Paradise PEGA2 EGA card instead of VGA.

carlostex wrote:Very nice system! The trinitron monitor is beautiful and i bet the picture looks amazing in person.

As far as the performance of the system i'm not too impressed. My 16 MHz AT clone based on a Octek Fox II board with Headland HT12 chipset scores 4044 Dhrystones in NSSI. Simply overclocked to 18MHz i get a score of 4512 Dhrystones. I've had an even slower 20 MHz board much slower than yours, the infamous M219 board. The chipset seems to be very important, as far as i know, Headland and VLSI seem to be the fastest. My graphics subsystem is probably much slower than yours though, since i use a Paradise PEGA2 EGA card instead of VGA.

But very nice system, love the case too!

Thanks! I like this case too - looks good and it's also well-built. I have 3 of them, unfortunately I damaged one while giving it the retrobrite treatment last summer. Left the front panel for too long in the heat and it got bleached and shrunk

Unfortunately the monitor must have seen heavy use during its life and is now severely lacking in contrast. I wish there were a way to revive it because the picture is very dull in its current state.

The Octek Fox II seems like a great board - I also have one but it needs repair. I believe the headland chipset is a later one though - I think the NEAT chipset is from around '89 so I'm not surprised the Headland beats it in the speed department. In the extended CMOS setup screen there are many settings that might give a performance increase but they're quite obscure so I haven't fiddled too much with them.

Coincidentally I also tried a PEGA2 in the system the other day and it's a nice match. I initially thought the 286-20 might be too fast for some games (e.g. DeathTrack) but it actually plays ok.